I so feel your exhaustion and frustration after just going through this. I do feel your foal is a quasi dummy foal like mine was. Both vets I called promised my foal would "suddenly wake up" and start nursing and acting more horse like. Both of them were exactly right. It was like a light switch. One thing I know is you cannot force a foal to nurse it just wont work. My guy was just mildly affected and yours sounds the same.
I was so worried bottle feeding ours for those first hours but both vets assured me again it would be fine and he would nurse. Again they were right.
He was born at 1210 in the afternoon and started nursing at 3 am.
Couple people emailed asking nicely if I was just fussing with him too much. The problem is they could not see on cam what I could see in person. That his sucking reflex was not strong enough and that he was not acting like a "normal" foal. (he was sucking on walls, buckets, wandering around, not paying attention to his dam, clinging to me) I knew I had to keep feeding him to get the colostrum in.
Once he "woke up" he finally acted like a foal and no longer ran to me and Kyle. It truly was like seeing a light switch turn on.
When mine started nursing he did it all on his own without any help
Im praying your guy does the same thing!!!